THE gannet was thought to be the one seabird immune to the food shortages which have caused devastation in colonies across Scotland.
Its famed tendency to eat almost anything, its hunting ability and a foraging range of hundreds of miles supposedly safeguarded the gannet from the mass breeding failures affecting colonies of such birds as the puffin, guillemot and kittiwake.
Conservationists have watched live on monitoring cameras as kittiwake chicks starved to death because their parents have been unable to find enough food to sustain them.
But now, scientists have found the first signs that even gannets - which will eat anything from tiny sandeels to large mackerel - are struggling to find enough food for their young.
While problems at a puffin colony on St Kilda show there is a local food shortage, the discovery that gannets are starting to suffer suggests marine life is in trouble throughout the food chain and over a wide area of the sea.
Research using tracking devices has found the birds have been flying farther from their nests at the world's largest single gannet colony on Bass Rock, off the East Lothian coast, to find food, with some flying to Norway - a round trip of more than 600 miles.
They have also increased their flying speeds in an attempt to get back to nest sites in time to relieve their mates.
Dr Keith Hamer, of Leeds University, said a lack of food appeared to be forcing more adult birds to do what was previously almost unthinkable for a gannet: abandon their chicks on the nest.
"The received wisdom was they don't leave chicks unattended and, quite often, one adult would come in and you'd have both birds there together for a while," Dr Hamer said.
"What's happened quite recently is gannets have been extending their foraging and trip durations so the bird at sea is away so long that the bird on the nest has to leave.
"An unattended chick is quite vulnerable, particularly on the Bass Rock where there are lots of non-breeders looking for nest sites. If they can kill the chick, then they can get the nest site."
A nest is of central importance to gannets as almost all will keep to the same site with the same mate for life. A study on Bass Rock found that while the percentage of chicks left alone at any one time was less than five per cent, about 70 per cent of chicks were left unattended at some point during the 13 weeks from hatching to fledging.
Gannets are a protected species, although inhabitants of Ness on Lewis are allowed to kill up to 2,000 a year to make the traditional delicacy, "guga". The birds are still breeding successfully, but the increasing struggle for food suggests fundamental problems beneath the waves.
Dr Hamer said: "We haven't had any years of breeding failures for gannets, but we know they have been working much harder. It looks as though things are turning bad for them.
"There is some evidence to suggest the fish the birds are bringing back are of poorer quality. The fish are there, but they have been growing badly because they cannot get enough food."
Dr Bryan Nelson, one of the world's leading experts on gannets, said the birds were "our most spectacular seabird with a six-foot wingspread, dramatic pale blue eye, dagger-like bill and this terrific plunge-diving ability".
Dr Nelson, who lived on Bass Rock from the early 1960s to the 1980s, said it was "extremely uncommon" for both parent birds to leave the nest in the 1960s, but in the last few years gannets on the island had been laying their eggs later in the season than usual, another sign of difficulties finding food.
He added: "They normally come back in late January, early February and the first egg could be laid in March. The mean laying date - the date on which the middle egg of all the eggs laid in the season - used to be 24 April.
"That's moved back a bit so now the mean laying date is into May, which means things have changed in the feeding situation in such a way that they are being slightly delayed in breeding."
Dr Nelson echoed Dr Hamer's warning that the problems faced by the gannet indicated a much wider problem affecting life beneath the waves.
He said: "It could be there are two factors at work here - the movement of prey species northwards due to global warming and a diminution in available prey due to overfishing.
"Alone among British seabirds, gannets have, until now, not shown any signs of chicks starving. They are still doing well, but they are just beginning to show the first signs [of trouble] - coming back to breed later and both parents having to forage at the same time.
"You can just sense that something is happening. And if the feeding is bad for gannets, something serious is happening to the marine food web."
Seabirds face misery of starvation and death
MANY seabird populations rose strongly in the late 20th century, but since the new millennium, several species have experienced starvation, misery and death, writes Ian Johnston.
The latest official survey, Seabird 2000, shows numbers of common guillemot, gannets and northern fulmars rose and while populations of herring gulls and kittiwakes fell, the overall picture looked fair.
However, in 2000, things turned sharply for the worse and since then, kittiwakes, guillemots, puffins, Arctic skua and others suffered serious breeding failures in colonies all around Scotland and beyond. Last year, starving guillemots were reported in unusual inland locations, including the centre of Glasgow and Crianlarich - and last autumn, 120 dead guillemots and razorbills were discovered near Loch Fyne, Argyll.
In colonies from the east coast to St Kilda, the survival rate of hatchlings has dropped to as low as one in five. Many effects have not yet been seen; most seabirds are counted as breeding pairs and guillemots, for example, take six years to reach maturity.
There were population crashes in the 80s and early 90s, largely due to a lack of food because of severe over-fishing of sand eels, a mainstay of many seabird diets, by industrial fisheries. But the latest declines appear to have been due to global warming. Changes in temperature and ocean currents seem to have changed the distribution of plankton populations to the detriment of sand eels and other small fish.
Birds have been forced to feed on less nutritious alternatives like the snake pipefish, which is a similar size to the sand eel but hard for hatchlings to digest. The result? Baby birds starving to death and, in some cases, whole colonies simply failing to breed.
Dr Norman Ratcliffe, senior research biologist at RSPB Scotland, said: "In 2000, we started to see these breeding failures recur. They have become worse and we have started to see diving species affected as well.
"I think for many species we are going to continue to see declines. More seabirds are going to be of conservation concern."
Tom Brock, chief executive of the Scottish Seabird Centre at North Berwick, said: "Things certainly seem to be changing fairly rapidly. Probably the most dramatic of all is what we are seeing with the kittiwakes."
He said this was seen in the breeding season from cameras monitoring a kittiwake colony near Dunbar: "Adults have been trying to feed snake pipefish to their chicks, but there's hardly any nutrition in it and the chicks are starving. The chicks are dying and we are watching this happen live on camera. It's horrendous."
The Scotsman's manifesto to protect the seas
The Scotsman has launched a campaign for urgent steps to be taken to protect our most precious marine wildlife.
A network of marine reserves and protected areas should be set up to properly safeguard sites such as St Kilda, a World Heritage Site, the Sound of Mull, an important area for whales and dolphins, and Loch Sween with its lagoons and tidal rapids.
This should be backed up by a system of marine spatial planning, effectively the zoning of areas for appropriate uses. This will safeguard important fishing grounds from offshore windfarm and other developments and allow humans to exploit the seas in the most sustainable way.
A single marine management organisation should be set up to administer this system to ensure this system is run efficiently.
Scotland should be given control of conservation out to the 200-mile boundary with international waters. At present the Scottish Government is in control out to 12 miles with the UK government responsible beyond that, an arbitrary boundary which makes little sense.
YOUR SUPPORT FOR OUR AGENDA
"Scottish waters should be under the control of the Scottish Government and there should be agreement on conservation areas on our sea beds."
Guga II, Rockall
"A great campaign, and a fantastic start. There's so much at risk under the waves, and such a bias towards the "needs" and "rights" of fishermen.
EdinBin, By the coast
"The time to take action on this is now, before it is too late."
The Forgotten Princes
"As a European I can see that Scotland's hidden shame is how it treats its wildlife. There used to be abundant sea trout on your west coast, now you have foreign-owned salmon farms with sea lice explosions and no sea trout and low-paid jobs in the salmon farm industry. "
"Great that you are bringing some of the problems of our oceans to the public's attention."
"Yup, I'm on board with this. My father-in-law used to run a scallop boat, but switched to prawns (because there are hardly any scallops left)."
Dave From Barra, Western Isles
"The sandeel is the basic food for everything in the sea. If you knock away the base of a food pyramid it collapses."